Once the president-elect becomes President Joe Biden on Wednesday, he'll be able to proceed on the agenda that helped him win the 2020 election. Many pledges are pegged to the first 100 days, but a few have been targeted for Day One — including rejoining the Paris climate accord.

Biden's predecessor, Donald Trump, withdrew from the accord, and rejoining it sends all the right international and domestic signals about the new administration's trust in science to make data-driven decisions, its resulting commitment to combat climate change, and its willingness to work multilaterally to try to solve transnational problems.

There is near unanimity among scientists about the effects of climate change. In fact, the most pernicious impacts are actually happening sooner than anticipated. Trump and many like-minded Republican lawmakers are resoundingly on the wrong side of science — and history. Their denial has made the U.S. an outlier in recognizing and reckoning with this existential threat.

Biden has no such scientific blind spot. Indeed, he sent a strong signal of his administration's intent when he named former Secretary of State John Kerry, who was instrumental in negotiating the Paris pact, to a cabinet-level position as special presidential envoy for climate. Kerry also will be a member of the National Security Council, a move the envoy said in a statement would treat "the climate crisis as the urgent national security threat that it is."

Indeed, the Pentagon long ago determined that climate change was a national security threat. Having the U.S. back in the 2015 pact — which according to the U.N. "aims to limit global warming well below 2 degree Celsius and as close to 1.5 degree Celsius as possible" and "increase economic and social ability to adapt to extreme climate" — will help businesses plan for the future and adapt and take advantage of an evolving marketplace.

"A lot of CEOs said it would be helpful to have some policy stability," Prof. Jessica Hellmann, director of the University of Minnesota's Institute on the Environment, told an editorial writer. "The signal is saying that we are going this way, which helps stabilize those commitments companies are making."

It also sends a signal about the commitments the U.S. is making. To the Paris accord, yes, and to the issue of climate change. But as profoundly, a presidential-level recommitment to working multilaterally to solve transnational problems. The climate change problem wasn't created by an individual nation, and it can't be solved by just one. "The commitment shows the international community we take responsibility for doing what's right," Hellmann said.

Rejoining the Paris climate accord is critical. And doing it so soon sends the right signal that Biden intends to restore America to a position of global leadership.

Like so many of the daunting challenges the country's 46th president will face, now comes the hard part. But with the commitment of leaders in government, business and the scientific community — along with the can-do of everyday Americans — it's a challenge that can, and must, be met.